OBJECTIVETo investigate whether Helicobacter pylori infection has any effects on the epithelial cell proliferation, apoptosis and P53 gene expression as well as its role in the pathogenesis of chronic gastritis.

METHODSSixty children with chronic gastritis were studied. All the children underwent upper digestive tract endoscopy and biopsy specimens were taken. Helicobacter pylori infection was determined with microscopic examination after Gimsa staining and the rapid urease test and 30 of the children were Helicobacter pylori positive and the other 30 were negative. The relation between the findings and cell proliferation was studied by immunostaining; the status of gastric apoptosis was tested by DNA fragmentation in situ using TdT-mediated dUTP biotin nick end labeling (TUNEL). Immunohistochemical method was used to detect the expression of P53 protein; CagA antibody was tested by Western blotting.

RESULTS(1) The proliferative index and apoptosis index in children with Helicobacter pylori infection with CagA positive gastritis were much higher than those of Helicobacter pylori negative gastritis patients [(11.56 +/- 4.21)% vs. (5.85 +/- 2.21)%, (10.58 +/- 5.31)% vs. (2.86 +/- 0.64)%, P < 0.01]. (2) The proliferative index and apoptosis index in 30 cases with Helicobacter pylori infection with CagA positive gastribis were much higher than 21 cases who were cured by effective drugs [(11.50 +/- 4.11)% vs. (3.74 +/- 2.30)%; (10.58 +/- 4.02)% vs. (3.74 +/- 2.30)%, P < 0.01]. (3) The expression of P53 protein in Helicobacter pylori with CagA positive gastritis children was much higher than that of Helicobacter pylori negative cases [(63% vs 16%), P < 0.1].

CONCLUSIONCagA positive Helicobacter pylori infection with gastritis improved gastric epithelial cell proliferation and apoptosis. The abnormal expression of P53 protein in gastric epithelium may play an important role in regulation of the processes.